Supercharged collector-ring assembly



Jan. 15, 1946. OS ETAL 2,393,066

SUPERCHARGED COLLECTOR RING ASSEMBLY Filed Jan. 28, 1943 A? v 9 I f WITNESSES: B A lg vlzu'ron d M 8/7/7/8 0.99 0/7 Y {Ev/7A 5. Powers ATTORNEY Patented Jan. 15, 1946 SUPERCHARGED COLLECTOR-RING ASSEltmLY Bennie A. Rose, Wilkinsburg, and Frank B. Powers, Pittsburgh 16, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 28, 1943, Serial No. 473,842

4 Claims.

Our invention relates primarily to high-altitude current-conducting contact-devices operating in air, for use aboard aircraft, for increasing the practical limits of the operating-speeds of the devices, or increasing the operating limits of the current densities in the brushes, or increasing the high altitudes at which the devices are. operable, beyond present limits. More specifically, our invention relates to Collector-ring The principal object of our present invention is to solve any such difliculty by superchanging the current-collector assembly, that is, to supply more air to the assembly, at a pressure higher than that which is encountered at high-altitude flight, preferably restoring the air-pressure to the neighborhood of the normal atmospheric pressure at sea level. Under some conditions, we may want to add means for increasing the waterassemblies or commutator assemblies which opervapor content, either with or without the superate in air, at such high speeds, at such highaltiv charging. tudes, or under such dry weather-conditions, that Our invention thus removes a limitation that operation is very short-lived in the absence of stands in the path of development of highour specia1 protective-measures. speed aircraft-generators, particularly when In a companion application of LeeFAB Kilgorze 5 utilized at low pressures approachin or and others, Serial No. ,4 4, filed e ruary of sea-level atmospheric pressure. 1943, and assigned to the Westinghouse Electric Two exemplary forms of embodiment of our 81 Manufacturing p y, an electric driveinvention are shown in the accompanying drawsystem for airplanes is set forth, utilizing highing, wherein i eq n y y m l ri m hin s perating at 20 Figure 1 is a longitudinal cross-sectional view t pp eds of fr m ab ut 1 00 r o t n per of the collector-end of a high-speed aircraftminute to about 20,000 revolutions per minute, generator embodying our invention, and these high Operat g-Sp eds being required in Fig. 2 is a similar view of a direct-current order to bring down the weight per horsepower. ma hine, At least some of these machines require collector- 25 As shown in Fig. 1, our invention is particurings, and our invention is particularly a plicable larly applicable to a synchronous machine 3, ha r. to the design and construction of suc highing a, stationary field member 4, and a highspeed collector-ring p rti la ly in Planes of speed rotating armature member 5 mounted in the high-altitude type. bearings B and having, for example, an over- AISO, 0X1 eXCiterS and Other direct-current hanging shaft-end 1 carrying two collector-rings dynamo-electric machines on aircraft, w q 8 for conducting direct-current through relatively high-altitude flight-congitionrsl obtain, brushilife stationary brushes 9 betfring ponblthe colligtog y be of the Order 0 an more BS5, rings. The rotor-mem 1- pre era y opera s under certain operating-conditions, even though t peed-range of t order of 15 000 revoluthe rating of th machine is not as high as would ti n per i ut or from, about 10,000 to about be desirable. In these direct-current machines, 20 000 revolutions per i t and th tggthe speed is high, but it cannot be as high as rings have a peripheral speed in the range it is possible to have in an alternating-current tween 10,000 d 13,000 feet per minute, more machine. Y or less, with the brushes bearing upon the pe- Our experience indicates that, at such high 40 ripheries of t ollector-rings, p and t high altitudes. the current- In accordance with our invention, particularly collecting operation may be extremely troublefor application on hjgh altitude air raft we some unde so conditions. as the brushis likely close the brushholders and collector-rings in a. to get red hot with excessive friction, and probchamber or housing member H, and we sump ably with non-uniform distribution of current charge this housing by any suitable means as because the carbon of the brush has a negative by means of a fan '2 blowing through an resistance-coefficient. Under such condit ons, m1et opemng '3 into the housing As shown in the brush W111 chatter and jump m its holder Fig 1 the fan I2 is the air-blowing means by and will quickly disintegrate, sometimes in a matt f inutes after such conditions have which ventilating-air is forced through the synw ell developed not only requiring a brushchronous other machine high'pressure ep l acement but also necessitating a recondipart of this ventilating'system being tapped tloning of the rotating current-collector part, by e inlet-means 3, to Supply air, under preseither ring or commutator, because of a roughe. t t o torous or co partment ened current-collecting surface. II. The housing is provided with a suitable shaft-seal H such as a carbon-ring type of seal, having carbon rings I5 and garter-springs l5.

Ventilation for the collector-ring assembly is provided by means of fins or fan-blades l1 formed on the sides of the collector-rings 8 for violently agitating or circulating the air within the housing H; and the housing is provided with fins l8, inside and outside, for facilitating the heattransfer from the inside air to the outside air which is blowing over the housing from the fan or blower I2, or as a result of the motion of the aircraft through the air. As most of the loss in a collector-ring current-collector is frictionloss, we reduce the losses by reducing the number of brushes to a minimum, and we work our brushes hard, at high current-densities, with the maximum possible ventilation, utilizing violently agitated air in the brush-chamber, and heatexchanging finned surfaces [9 on the brushholder.

In some cases, it may be desirable to control the humidity, as well as the pressure, of the air within the collector-ring housing H, and this may be done by any convenient means, exemplified by a water-dropper 2| which introduces an occasional drop of water into the collector-ring chamber.

In operation, when the plane on which the synchronous machin 3 is mounted goes up to high altitudes, our invention makes it possible to operate the collector-ring chamber in air at something like sea-level atmospheric pressure, whereas the ambient pressure outside of the housing H may fall to as low as A to A of an atmosphere. In this way, we avoid disintegration of the brushes 9 as a result of excessive friction for lack of an adequate film of (preferably moist) air oarried around by the surface of the ring and normally preventing excessive brush-friction.

Our invention is also applicable to directcurrent commutators, where the peripheral-speed limits are somewhat lower, approximately in the range between about 7,000 and about 10,000 feet per minute, but where the same, or a similar, problem exists as to rapid brush-wear and disintegration at high-altitudes, where the air is not of sufficient density to properly lubricate the brush-contact surface. In Fig. 2, we show our invention applied to a direct-current machine 23, having a commutator 24 and brushgear 25. The brushgear 25 is enclosed in a housing 25 which is supercharged from a suitable compressed-air source at 21. Th housing 26 must make a farily air-tight joint with the rear end of the commutator, and to this end, the commutator is somewhat elongated beyond its usual requirements, and the brushes 25 are placed at the front end of the commutator. At the rear end of the commutator 24, the housing 26 makes a seal through sealing-rings 28 which bear upon a steel sleeve 29 which is insulated from the cylindrical commutator-surface by an insulating sleeve 30.

We claim as our invention:

1. A high-altitude high-speed rotating machine for use aboard aircraft, said machine having a current-collecting assembly comprising one or more current-collecting parts having a cylindrical current-collecting surface rotating at a peripheral speed at least as high as about 7,000 feet per minute, and one or more current-collecting brushes bearing on said cylindrical currentcollecting surface, said machine having a separate housing enclosing said current-collecting assembly including said brushes but not including the rest of said machine, a machine-ventilating means for causing a relatively large volume of ventilating-air to blow rapidly through the machine, and means for tapping a high-pressure part of said machine-ventilating system to serve as a supercharging-means for supplying air to said housing at a pressure higher than the ambient atmospheric pressur prevailing, at the moment, outside of said housing, at least during high-altitude flights, said machine having six openings for maintaining a free continuous circulation of ventilating-air, and said housing having one or more relatively restricted intakeopenings to the atmosphere, said opening or openings being directed toward the exhaust-air of said machine so as to collect a part of said exhaust-air, said housing being otherwise substantially air-tight.

2. The invention as defined in claim 1, in combination with moisture-adding means, for increasing the water-vapor content of the air within said housing.

3. A high-altitude high-speed rotating machine for use aboard aircraft, said machine having a current-collecting assembly comprising one or more current-collecting parts having a cylindrical current-collecting surface rotating at a peripheral speed at least as high as about 7,000 feet per minute, and one or more current-collecting brushes bearing on said cylindrical currentcollecting surface, in combination with means for providing a separate compartment for said current-collecting assembly, and a dual-purpose fan carried by the machine for forcing a relatively large volume of ventilating-air rapidly through the machine and for supp yin air, under pressure, to said compartment, said machine having air-openings for maintaining a free continuous circulation of ventilating-air, and said compartment having one or more relatively restricted intake-openings to the atmosphere, said opening or openings being directed toward the exhaust-air of said machine so as to collect I. part of said exhaust-air, said compartment being otherwise substantially air-tight.

4. The invention as defined in claim 3, in combination with moisture-adding means, for increasing the water-vapor content of the air within said compartment.

BENNIE A. ROSE. FRANK B. POWERS. 

